Your temp is a bit on the low side and if it was me i'd bring it up to about 22deg, each temp extreme will probably make the fish a bit lethargic, co2 could also be a reason for them not being as active with some needing time to adapt in my experience so far (ottos especially)
Concentrate on doing a pH profile to get the co2 spot on and dose 4ml ferts and see how you get on, rule out 1 by 1 and you'll sort it
Try to forget about excess ferts being an issue mate as it'll just hinder you addressing the problem, many of us dose EI which is well over what you're dosing with no green water or algae issues
Yeah good advice mate thanks.
Temps I think have been hard to stabilise since using a sump for some reason it’s colder in the tank as it has to travel up after.
Algae colouring the water do you think or something else? I’m thinking of using another Chihiros steriliser in there anyway soon.
If co2 all fish would be struggling wouldn’t they? Like I say it doesn’t seem like the drop checker is showing much - I’m on about 2-2.5 bps on co2 and sump degasses some too.
The change in behavior is odd though and fish swimming losing balance as if ill? Fish are very skittish too the Rummys but could be the species too?
Cheers
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